/*
 * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
 * Copyright (C) 2016 Furrtek
 *
 * This file is part of PortaPack.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include "modems.hpp"
#include "serializer.hpp"

#include "portapack_persistent_memory.hpp"

using namespace portapack;

namespace modems {

void generate_data(const std::string& in_message, uint16_t* out_data) {
    uint8_t parity_init, parity, bits, bit, cur_byte;
    uint16_t ordered_word;
    size_t bytes;

    serial_format_t serial_format = persistent_memory::serial_format();
    size_t message_length = in_message.length();

    if (serial_format.parity == ODD)
        parity_init = 1;
    else
        parity_init = 0;

    uint8_t data_bits = serial_format.data_bits;

    for (bytes = 0; bytes < message_length; bytes++) {
        parity = parity_init;
        cur_byte = in_message[bytes];
        bit = 0;

        if (serial_format.bit_order == MSB_FIRST) {
            ordered_word = cur_byte;
            for (bits = 0; bits < data_bits; bits++) {
                bit = (cur_byte >> bits) & 1;  // Get LSB
                parity += bit;
            }
        } else {
            ordered_word = 0;
            for (bits = 0; bits < data_bits; bits++) {
                bit = (cur_byte >> bits) & 1;  // Get LSB
                parity += bit;
                ordered_word |= (bit << ((data_bits - 1) - bits));  // Set MSB
            }
        }

        if (serial_format.parity) {
            ordered_word <<= 1;
            ordered_word |= (parity & 1);
        }

        for (bits = 0; bits < serial_format.stop_bits; bits++) {
            ordered_word <<= 1;
            ordered_word |= 1;
        }

        out_data[bytes] = ordered_word;
    }

    out_data[bytes] = 0;  // End marker
}

// This accepts a word with start and stop bits removed !
uint32_t deframe_word(uint32_t raw_word) {
    uint32_t cur_bit, deframed_word{0};
    size_t bit;

    serial_format_t serial_format = persistent_memory::serial_format();

    /*if (serial_format.parity == ODD)
                parity = 1;
        else
                parity = 0;*/

    size_t data_bits = serial_format.data_bits;

    // Ignore parity for now
    if (serial_format.parity)
        raw_word >>= 1;

    if (serial_format.bit_order == LSB_FIRST) {
        // Reverse data bits
        for (bit = 0; bit < data_bits; bit++) {
            cur_bit = raw_word & 1;

            deframed_word <<= 1;
            deframed_word |= cur_bit;

            // parity += cur_bit;

            raw_word >>= 1;
        }

        return deframed_word;
    } else
        return raw_word;
}

} /* namespace modems */
